金花茶遗传多样性的ISSR分析

采用ISSR分子标记对金花茶的4个自然分布居群的126份样品的遗传多样性水平进行了研究。用12条引物,共检测到105个清晰的扩增位点,其中多态性位点79个,多态位点百分率(PPB)为75．24％。采用POPGENE软件进行分析,结果表明：居群总的Nei’s基因多样性指数为0．2302,Shannon信息多态性指数为0．3502,金花茶总的遗传多样性水平较高。但金花茶居群内的遗传多样性相对较低。基因分化系数为0．5752,遗传变异主要存在于居群间。用NTSYS软件对样品进行UPGMA聚类分析,结果4个居群的样品各自聚在一起,而金花茶两间断分布区区内的居群又各自聚在一起。金花茶4个居群间的遗传距离与地理距离呈显著的正相关(r=0．68261,P=1．0000)。     

茉莉酸甲酯处理对绿豆下胚轴质膜H+-ATPase水解活力及磷酸化水平的影响

运用γ-32P示踪、蛋白激酶和磷酸酶抑制剂药理实验探讨茉莉酸甲酯(MeJA)对质膜H -ATP酶水解活力及磷酸化水平的影响.结果如下:MeJA可促进H -ATP酶水解活力30%;斑蝥素和岗田酸促进了MeJA对质膜H -ATP酶的刺激作用;星形孢菌素和白屈菜红碱削弱了MeJA对质膜H -ATP酶的刺激作用.H -ATP酶活力变化同时,其上的γ-32P标记量发生变化.Ca2 对H -ATP酶水解活力有很大的刺激作用,但对MeJA促进H -ATP酶活力的作用没有进一步的影响.根据这些结果可以得出结论:MeJA刺激质膜H -ATP酶水解活力的变化与H -ATP酶磷酸化水平呈正相关,并且催化这一作用的蛋白激酶可能不依赖于Ca2 ,而蛋白磷酸酶依赖于Ca2 .     

植物体中的MAPK

促细胞分裂剂激活性蛋白激酶（MAPK）是一类存在于各种真核生物体中的丝氨酸/苏氨酸型蛋白激酶。它被上游激活因子MAPKK磷酸化而激活,并通过将底物蛋白上的丝氨酸和苏氨酸残基磷酸化而传递信号。它与其他一些信号分子组成MAPK级联信号通路,接受外界刺激信号,将信号转入细胞内,影响特定基因的表达,它的作用受到不同因子的调节。本文介绍了植物体中的MAPK的结构特点、作用机理、生物功能以及MAPK级联信号通路的调节。     

Closing the carbon budget of estuarine wetlands with tower-based measurements and MODIS time series

Compared to other ecosystems, estuarine ecosystems have distinct carbon flux dynamics – the lateral carbon flux incurred by tidal activities, and methane generation under the anaerobic conditions of wetland soils. The conventional estimation of gross primary production (GPP) based on the light use efficiency (LUE) model used for non‐wetland terrestrial ecosystems, therefore, cannot be applied directly to estuarine wetland ecosystems. In this paper, we estimated the 2005's annual carbon budget of an estuarine wetland on Chongming Island, Shanghai, and partitioned the losses of carbon due to lateral tidal dynamics and anaerobic methane production using an innovative technique. The average GPP calculated from eddy covariance between March and November was 261.79 μmol m^?2 day^?1, whereas that from the LUE model was 58.84 μmol m^?2 day^?1. The correlation coefficient between GPP simulated from the LUE model and that calculated from flux tower data was low in the growing season (R²=0.55). We hypothesized that tidal activities and uncounted methane release were responsible for the difference, which can be predicted from measurements of remote sensing products such as land surface water index (LSWI), evapotranspiration (ET), and tide height (TH). We developed an integrated GPP model by combining the LUE model and an autoregression model to estimate carbon budget. The average GPP from the modified model increased to 263.38 μmol m^?2 day^?1, and R² for the correlation between the simulated and calculated data increased to 0.88, demonstrating the potential of our technique for GPP estimation and quantification of seasonal variation in estuarine ecosystems. The approach developed in this study has great potential for correcting unavoidable errors when estimating carbon budget of coastal wetlands. Furthermore, global warming is expected to accelerate sea level rise, which may enhance the effect of tidal activities and increase the difficulty in estimating coastal carbon budgets using conventional methods.     

Comparative genomics and phylogenetic analysis of S. dysenteriae subgroup

Shigella spp are the pathogen of bacillary dysentery, the leading intestinal contagious disease in China. According to the O antigen, Shigella spp can be sub-grouped into four species: S.dysenteriae, S. flexneri, S. boydii and S. sonnei, also known as Shigella sub-groups A, B, C and D. In developing countries, S. dysenteriae A1, one of the thirteen serotypes in A sub-group, resulted in extremely serious bacterial diarrhea with mortality of 7%[1]. Traditional classifications were unsucces…     

壳梭孢素对质膜H~ -ATPase活力影响机制的研究进展

壳梭孢素 (FC)作为一种重要的研究工具广泛用于研究酸介导的生长反应和依赖于质子推动力的膜运输系统 ,FC刺激质膜H _ATPase的活性是通过FC结合蛋白 (FCBP)与H _ATPase发生作用。FCBP是 1 4_3_3蛋白家族成员之一     

DIFFERENTIAL THRESHOLD AND PSYCHOPHYSICAL POWER FUNCTION OF SWEETNESS SENSATION: APPLIED PSYCHOPHYSICS AND PROSPECT THEORY ON FORMULATING BAKING PRODUCTS

The main purpose of this project was to develop the optimal sweetness sensation framework for baking products. Phase 1 was designed to measure consumers' differential thresholds of sweetness sensation when the sweetener contents of various sweetener‐leveled products were increased and lowered by using the constant stimuli method. Results indicated that the consumers' differential thresholds increased when the initial sweetener levels of products increased. Phase 2 was designed to establish the psychophysical power function of sweetener‐content changes and consumers' psychological sensation of products with different sweetener levels by adopting the magnitude estimation method. Regardless of the initial sweetener levels of products, the results showed that consumers perceived the products as less sweet immediately after the sweetener contents of products dropped by even a small amount; however, consumers perceived products as sweeter only when products dramatically increased in contents of sweetener.     

猫颈部和腹部迷走神经加压反应的比较研究

刺激麻醉猫颈部和腹部迷走神经中枢端引起的升压反应,不但反应模式有别,其升压机制也不同。颈部迷走加压反应是在出现快速降压之后的一个缓慢持续的血压升高,而腹部迷走加压反应则是一个快而短暂的升压反应。在颈迷走加压反应出现的同时伴有血浆加压素(AVP)的增加,但血浆肾素活性(PRA)及血管紧张素 Ⅱ(ANG Ⅱ)和肾神经放电(RND)都有不同程度的下降。腹部迷走加压反应的出现则伴有 RND,PRA 和血浆 ANG Ⅱ 水平的增加,但 AVP 无明显改变。兴奋同一迷走神经颈腹段传入纤维引起的升压效应之所以不同主要是由于传入纤维的来源和在中枢的投射部位不同,因而升压机制也各异。     

家鸽臂丛和坐骨神经传入冲动在纹状体的投射

在53只家鸽的纹状体上系统地探查了刺激臂丛和坐骨神经所引起的平均诱发电位。结果发现,臂丛传入的投射区位于新纹状体、上纹状体和外纹状体之内,坐骨神经传入投射区则分别与臂丛传入的新纹状体投射区和上纹状体部分投射区重合;臂丛和坐骨神经投射区均接受身体两侧的传入。作者认为,家鸽纹状体内的前、后肢躯体感觉传入投射区是分散的,并非形成一个集中的中枢;前肢的投射区较大,可能与机能分化有关,身体不同部位的传入冲动在同一投射区内的会聚,对于肢体活动的整合具有重要意义。     

Assembly of lamins in vitro

After lamins A,B and C were isolated and purified from rat liver,their assembly properties were examined by electron microscopy and scanning tunneling microscopy by electron microscopy and scanning tunneling microscopy using negative staining and the glycerol coating method,respectively.By varying the assembly time or the ionic conditions under which polymerization takes place,we have observed different stages of lamin assembly,which may provide clues on the structure of the 10 nm lamin filaments.At the first level of structural organization,two lamin polypeptides associate laterally into dimers with the two domains being parallel and in register.At the second level of structural organization,two dimers associate in a half-staggered and antiparallel fashion to form a tetramer 75 nm in length.At the third level of structural organization,4-10 lamin tetramers associate laterally in register to form 75 nm long 10nm filaments,which in turn combine head to head into long,fully assembled lamin filaments.The assembled lamin filaments are nonpolar.